Jean Piaget’s (1896–1980) cognitive developmental theory offers descriptions and explanations of children’s mental and social-emotional growth from infancy to adolescence. Piaget developed creative methods to assess children’s thinking in content areas that are relevant for early education, including language and symbol use, moral judgment, mathematics, logical reasoning, and spatial relationships. Cognitive developmental theory is the basis for constructivist approaches to early education that provides a framework for determining the aims of early education and teachers’ roles in creating inclusive and effective learning environments for young children.